8 The American Geologist. Juiy, isss 
been described by N. H. Winchell,* Irving,! A. Wincliell,+ Van 
Hisei^ and Lawson, || and no one has ever questioned it. It is 
not necessary in this connection to discuss the age of the above 
mentioned vertical schists, concerning which some question has 
been raised,** but it is sufficient for the present purpose to con- 
sider only the age of the granite. From all our knowledge of 
granite it is never known to have been formed in or to have pene- 
trated strata near the surface; we are thus forced to conclude 
that after this granite came into its present place and condition 
and before the Animike was deposited there must have been a 
long period of erosion, during which all the overlying surface 
rocks were removed. Thus there is an enormous difference in 
age between the Animike and the granite, the former being 
separated from the latter by a great unconformity and as long a 
period of erosion as is knowai in lake Superior geology. 
Rtdation of tlie Ogishke coiigJomerate to the Sagioioga (jranite. 
This granite has been traced in numerous exposures from Grun- 
flint lake to the western side of Saganaga lake, and there can be 
no doubt that the granite which comes in contact with the 
Keewatin near the western side of the latter lake is the same as that 
underlying the Animike on the north side of Gunflint lake. On the 
northwestern corner of Saganaga lake Lawson has found this 
granite in direct contact with the Ogishke conglomerate, where 
the granite cut the conglomerate and the Keewatin rocks in a 
truly irruptive manner, tt Recently the writer has been enabled 
to supplement the observations of Lawson by finding another 
contact betw^een the conglomerate and the granite near the south- 
western corner of the granite area. At this place the irruptive 
nature of the granite in the clastic rocks is clearly seen ; it cuts 
across the strike of the conglomerate and lias forced its way in 
between the different layers. The granite has also been found 
*Geol and Nat Hist. Survey of Minn., 9th (1880) Ann. Kept, p. 82; 
10th (1881) Ann. Kept., p. 88; I6tli (1887) Ann. Kept., pp. 67, 69. 
tAmer. Jour. Sci., iii, vol. xxxiv, p. 261, Oct ,1887; U. S. Geol. Survey, 
7th Ann. Kept., p. 421. 
JGeol. and Nat. Hist. Survev of Minu.. 16th (1887) Ann. Kept., pp. 283-269, 
357; Amer. Jour. Sci., iii, vol.-xxxiv, p. 314, Oct., 1887; Ameh. Geologist, 
vol. I, pp. 14-24, Jan., 1888; Bull. Geol. Soc. Amer., vol. i, pp. 386-388. 
§U. S. Geol. Survey, 10th Ann. Rept., pi. xlii. 
||Amer. Geologist, vol. vii, p. 324, May, 1891. 
**Bull. Geol. Soc. Amer., vol. i, pp. 387-393. 
ttAMER. Geologist, vol. vii, p. 324, May, 1891. 
